fix(debugger): open the Debug window on Console, and on the view last picked (#3316)

The Debug window switched to Console only when it was open while the session was starting; a window opened later mounted on Threads & Variables, and a remount forgot the user's choice. It now opens on Console until a view is picked, then on the view last picked; a breakpoint or exception still brings Threads & Variables forward.

src/features/debugger/__tests__/toolWindow.test.tsx

@@ -228,6 +228,20 @@ describe("debug tool window", () => {
     expect(console.getAttribute("aria-selected")).toBe("true");
   });
 
+  it("opens on Console for a running session, and on the view last picked when shown again", () => {
+    useDebug.setState({ sessions: { 1: { ...session, status: "running" } }, active: 1 });
+    const first = render(<DebugToolWindow />);
+    expect(screen.getByRole("tab", { name: "Console" }).getAttribute("aria-selected")).toBe("true");
+    fireEvent.click(screen.getByRole("tab", { name: "Threads & Variables" }));
+    first.unmount();
+    const again = render(<DebugToolWindow />);
+    expect(screen.getByRole("tab", { name: "Threads & Variables" }).getAttribute("aria-selected")).toBe("true");
+    fireEvent.click(screen.getByRole("tab", { name: "Console" }));
+    again.unmount();
+    render(<DebugToolWindow />);
+    expect(screen.getByRole("tab", { name: "Console" }).getAttribute("aria-selected")).toBe("true");
+  });
+
   it("renders session tabs, views, frames and typed variables", async () => {
     useDebug.setState({ sessions: { 1: session }, active: 1 });
     render(

src/features/debugger/ui/DebugToolWindow.tsx

@@ -103,6 +103,9 @@ function MoreActions() {
 
 type Tab = "variables" | "console" | "memory";
 
+/** The view the user last picked; the tool window opens on it again (Console until one is picked). */
+let chosenTab: Tab = "console";
+
 function statusText(s: DebugSession): string {
   if (s.status === "terminated") return s.exitCode != null ? `Finished · exit code ${s.exitCode}` : "Finished";
   if (s.status === "starting") return "Starting…";
@@ -149,7 +152,7 @@ export function DebugToolWindow() {
     session: number | undefined;
     status: DebugSession["status"] | undefined;
     tab: Tab;
-  }>({ session: undefined, status: undefined, tab: "variables" });
+  }>({ session: undefined, status: undefined, tab: chosenTab });
   if (active && (view.session !== active.startedAt || view.status !== active.status))
     setView({
       session: active.startedAt,
@@ -232,7 +235,10 @@ export function DebugToolWindow() {
               aria-selected={tab === id}
               aria-controls={`debug-panel-${id}`}
               className={clsx(styles.tab, tab === id && styles.tabActive)}
-              onClick={() => setView({ session: active.startedAt, status: active.status, tab: id })}
+              onClick={() => {
+                chosenTab = id;
+                setView({ session: active.startedAt, status: active.status, tab: id });
+              }}
             >
               {tx(label)}
             </button>